Abstract. The present study examines whether Positive Psychotherapy (PPT) fulfills the three common efficacy factors of psychotherapy postulated by Grawe et al. (1994) and in doing so takes the therapists’ assessment of the common factors, the length of professional experience of therapists and multiple times of measurement into account. 207 outpatients (66 males, 41 females) and their therapists – who were trained in PPT – evaluated the fulfillment of the three common factors after an individual therapy session. Results provide support for the effectiveness of PPT: patients and therapists both assessed PPT to fulfill the three common efficacy factors. However, patients perceived all three factors to be fulfilled to an even higher degree than therapists did. Additionally, two of the common factors were judged to be more fulfilled when the treating therapist had more rather than less professional experience. Lastly, patients experienced therapy as even more effective over time. The verification of the effectiveness of Positive Psychotherapy via an explicit measurement of the common efficacy factors leads to a gain of knowledge and has important implications for psychotherapists practicing and teaching PPT alike. Furthermore, the present study provides new and interesting approaches for future research.
Keywords: psychotherapy research, Positive Psychotherapy, effectiveness research, common efficacy factors, outpatient treatment.